The present invention relates to mechanisms capable of achieving a precisely-timed intermittent operation.
The structure of the invention is capable of being used, for example, on sheet material such as tapes or cards for the purpose of achieving punched tapes or punched cards.
In order to provide punched tapes or punched cards the sheet material, such as the tapes or cards, must be intermittently fed in such a way that it undergoes intermittent feeding movements which respectively alternate with dwell intervals during which the sheet material remains stationary.
While the sheet material is stationary it is acted upon by a reciprocating tool such as a punch. By restricting the operation of the reciprocating tool on the sheet material to the above dwell intervals thereof, it is possible for the tool to operate on stationary sheet material while feeding of the sheet material takes place during those intervals when the punch or other tool does not operate on the sheet material. In this way it is possible to both feed and punch the sheet material without any interference between these operations.
Conventional devices for achieving products such as punched sheet material generally include as their sources of power relatively large powerful magnets which must be precisely operated in suitable timed relationship for bringing about operations such as punching and feeding of sheet material.
Such conventional structures are undesirably large, so that they occupy too much space, they consume a relatively large amount of power, and because of factors such as friction and inertia of the components of such structures, it is difficult on the one hand to achieve the precise timed relationship which is required to prevent interference between operations such as feeding and punching, and if in fact such a desired time relationship is maintained, then the output is reduced inasmuch as the successive dwell and feed intervals of the sheet material cannot follow each other with the desired rapidity.